Field of the Invention
The present invention relates to a method for assessing products used in cellular biology, for example, in vitro fertilization. Also disclosed is a quality control assay for use in clinical Assisted Reproductive Technologies (ART).
Description of the Related Art
The in vitro fertilization (IVF) laboratory plays a fundamental role in the treatment of infertile couples. Ensuring proper Quality Control (QC) in the IVF laboratory is critical to the success of any IVF program, as the environment of the laboratory can alter the quality of the embryos produced. An optimal culture medium and a stable environment are necessary for the successful development of human embryos in vitro. The ultimate role of the embryology laboratory is to maintain the inherent viability of the gametes and embryos in an environment outside the female reproductive tract. The dynamic nature of pre-implantation embryo development is unique because, unlike somatic cell culture, embryos are constantly and rapidly changing, both in morphology and function (Leese 1991; Bavister 1995).
During development, pre-implantation embryos change rapidly, in just a matter of days, from a metabolically quiescent, undifferentiated single cell under the genetic control of maternal transcripts into a dynamic, multi-celled embryo that has developed homeostatic mechanisms and its own functioning genome (Leese 1991; Lane 2001; Gardner et al. 2005). The early embryo, which depends on a pyruvate-based metabolism and is solely dependent on mitochondrial oxidative phosphorylation for energy production; like a unicellular organism, the early embryo lacks many key regulatory functions for pH and osmotic control. After compaction at the eight- to 16-cell stage (dependent on species), there is a change in metabolic control to a highly glycolytic metabolism. Concomitantly, there is also a marked transition in the functional complexity of other cellular mechanisms as the embryo's physiology becomes more like that of a somatic cell. It is the initially crude nature of homeostatic regulation in the early embryo and its subsequent development through later stages of pre-implantation development that pose significant challenges in the laboratory. Maintenance of a favorable in vitro environment is essential for maximizing viability and promoting ongoing development.
Perturbations to the environment surrounding the embryo during development in culture, relative to “normal” conditions encountered in the reproductive tract, result in reduced embryo viability and impaired development. As discussed below, there is a need for objective, sensitive, and reproducible methods and assays for testing materials used in human IVF for embryo toxicity as well as growth promoting and inhibiting factors.